asked on

reading mp3 id3 tags in java...

I am trying to figure out how to read the id3 tag of an mp3 file with java. I think it is a fixed width thing at the end of the file... so is there a way to open a file and get to the end and work backwards or something?

Droby10

sure...it's been awhile, i'm going off the top of my head, and i don't have a reference available...so this may be a little off.

import java.io.*;

public static void main ( String args[] ) {
try {
File f = new File ( args[0] );
FileInputStream fis = new FileInputStream ( f );
int flen = fis.available();
byte sig[] = new byte [ 3 ];
byte artist[] = new byte [ 30 ];
byte title[] = new byte [ 30 ];
byte album[] = new byte [30];
byte genre[] = new byte [1];
byte comments = new byte [30];

int id3len = sig.length + artist.length + title.length + album.length + genre.length + comment.length;

fis.skip ( len - id3len );
fis.read ( sig );
fis.read ( artist );
fis.read ( title );
fis.read ( album );
fis.read ( genre );
fis.read ( comments );
} catch ( Exception e ) {
e.printStackTrace();
}
}

also, this code is for id3 version 1 only...which isn't used as much anymore...

id3 version 2 allowed title-streaming, embeded content...etc, and is much more robust...it's also much more difficult to filter as its embeded within the frames of an mp3 document.

Droby10

just realized how ugly the code was...be sure to check verify after all of the reads...and close the inputstream at the end.

AndyBeckwith

ASKER

do you have any info on the v2 tags?

Droby10

no...but here's the definitive resource..

http://www.id3.org/
http://www.id3.org/develop.html
http://www.id3.org/id3v2.4.0-structure.txt

you'll also find links for source documentation at

http://id3lib.sourceforge.net/

-hope this helps.

Droby10

and actually here's some java source...

http://www.rabbitfarm.com/site/id3.html

AndyBeckwith

ASKER

Back to your original code...

This is what I did, and it still wont work...

~~~ code ~~~
import java.io.*;
public class ReadId3 {

public static void main ( String args[] ) {
try {
File f = new File ( args[0] );
FileInputStream fis = new FileInputStream ( f );
int flen = fis.available();
byte [] sig = new byte [ 3 ];
byte artist[] = new byte [ 30 ];
byte [] title = new byte [ 30 ];
byte album[] = new byte [30];
byte genre[] = new byte [1];
byte comments[] = new byte [30];

int id3len = 124;

fis.skip ( flen - id3len );
fis.read ( sig );
fis.read ( artist );
fis.read ( title );
fis.read ( album );
fis.read ( genre );
fis.read ( comments );
} catch ( Exception e ) {
e.printStackTrace();
}

for( int i = 0; i < 30; i++ ){
System.out.print( "" + title[ i ] );
}

}
}
~~~ end code ~~~

I still get this error:

~~~ error ~~~
ReadId3.java:31: cannot resolve symbol
symbol : variable title
location: class ReadId3
System.out.print( "" + title[ i ] );
^
1 error
~~~ end error ~~~

I cant seem to force it to a string...

ASKER CERTIFIED SOLUTION

Droby10

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sudhakar_koundinya

No comment has been added lately, so it's time to clean up this TA.
I will leave a recommendation in the Cleanup topic area that this question is:

-- Points to Droby10

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